unsetenv

Remove environment variable

Since R2022b

Syntax

unsetenv(varname)

Description

unsetenv(varname) removes the operating system environment variable varname. If any elements in varname do not exist, then unsetenv has no effect.

example

Examples

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Create and Test Environment Variable

Open Live Script

Create environment variable myVar, and then check that it exists.

setenv("myVar","myValue");
isenv("myVar")

ans = logical
   1

Remove myVar, and then check that it no longer exists.

unsetenv("myVar");
isenv("myVar")

ans = logical
   0

Create and Test Multiple Environment Variables

Open Live Script

Create multiple environment variables, and then check that they exist.

setenv(["Var1" "Var2" "Var3" "Var4"],["Val1" "Val2" "Val3" "Val4"]);
isenv(["Var1" "Var2"; "Var3" "Var4"])

ans = 2×2 logical array

   1   1
   1   1

Remove two of the environment variables using unsetenv, and then check that they no longer exist.

unsetenv(["Var1" "Var4"]);
isenv(["Var1" "Var2"; "Var3" "Var4"])

ans = 2×2 logical array

   0   1
   1   0

You can also remove environment variables using setenv with missing. Change the value of one environment variable and remove another.

setenv(["Var2" "Var3"],["ValB" missing]);
isenv(["Var1" "Var2"; "Var3" "Var4"])

ans = 2×2 logical array

   0   1
   0   0

Input Arguments

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`varname` — Environment variable names
string scalar | character vector | string array | cell array of character vectors

Environment variable names, specified as a string scalar, character vector, string array, or cell array of character vectors.

Example: "PATH"

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

Code generation does not support the use of unsetenv inside parfor loops.

Version History

Introduced in R2022b